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Query: UMLS:C0019829 (Hodgkin's disease)
 30,247 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The origin of the action potential in neurones has yet to be answered satisfactorily for most cells. We present here a five-conductance model of the somatic membrane of the mature and intact sympathetic neurone studied in situ in the isolated rat superior cervical ganglion under two-electrode voltage-clamp conditions. The neural membrane hosts five separate types of voltage-dependent ionic conductances, which have been isolated at 37 degrees C by using simple manipulations such as conditioning-test protocols and external ionic pharmacological treatments. The total current could be separated into two distinct inward components: (1) the sodium current, INa, and (2) the calcium current, ICa; and three outward components: (1) the delayed rectifier, IKV, (2) the transient IA, and (3) the calcium-dependent IKCa. Each current has been kinetically characterized in the framework of the Hodgkin-Huxley scheme used for the squid giant axon. Continuous mathematical functions are now available for the activation and inactivation (where present) gating mechanisms of each current which, together with the maximum conductance values measured in the experiments, allow for a satisfactory reconstruction of the individual current tracings over a wide range of membrane voltage. The results obtained are integrated in a full mathematical model which, by describing the electrical behaviour of the neurone under current-clamp conditions, leads to a quantitative understanding of the physiological firing pattern. While, as expected, the fast inward current carried by Na+ contributes to the depolarizing phase of the action potential, the spike falling phase is more complex than previous explanations. IKCa, with a minor contribution from IKV, repolarizes the neurone only under conditions of low cell internal negativity. Their role becomes less pronounced in the voltage range negative to -60 mV, where membrane repolarization allows IA to deinactivate. In the spike arising from these voltage levels the membrane repolarization is mainly sustained by IA, which proves to be the only current sufficiently fast and large enough to recharge the membrane capacitor at the speed observed during activity. Different modes of firing coexist in the same neurone and the switching from one to another is fast and governed by the membrane potential level, which makes the selection between the different voltage-dependent channel systems. The neurone thus seems to be prepared to operate within a wide voltage range; the results presented indicate the basic factors underlying the different discrete behaviours.
Prog Biophys Mol Biol 1991
PMID:A five-conductance model of the action potential in the rat sympathetic neurone. 205 76

Previous studies using Southern blot analysis or in situ hybridization have shown that approximately 20% of patients with Hodgkin's disease have Epstein-Barr virus (EBV) in involved tissues. We used the more sensitive polymerase chain reaction (PCR) technique to determine if a higher percentage of EBV could be detected. Of the 16 Hodgkin's disease patients studied, the PCR technique detected EBV in eight (50%). No prognostic significance was associated with the presence of EBV in the eight EBV-positive patients, and the presence of EBV was not associated with B cell monoclonality.
Mol Carcinog 1990
PMID:Detection of Epstein-Barr viral genomes in lymph nodes of Hodgkin's disease patients. 215 58

A characterization of the properties of voltage-gated sodium channels expressed in the human cerebellar medulloblastoma cell line TE671 is presented. Membrane currents were recorded under voltage clamp conditions using the patch clamp technique in both the whole-cell and the excised-patch configurations. Macroscopic sodium currents display a typical transient time course with a sigmoidal rise to a peak followed by an exponential decay. The rates of early activation and subsequent inactivation accelerate and approach a maximum in response to test potentials, V, of greater depolarization. The magnitude of peak sodium current increased from negligible values below V = -50 mV and reached a maximum at V = -3.6 mV +/- 2.7 mV (mean +/- S.E.M., n = 12). Sodium currents reversed at V = + 70 mV, near the predicted Nernst equilibrium potential for a Na+ selective channel. The peak sodium conductance, gpeak increased with depolarizing voltages to a maximum at V = approximately 0 mV, exhibiting half-activation voltage at V approximately equal to -36.8 mV and an e-fold change in gpeak/9.5 mV. The Hodgkin-Huxley inactivation parameter h infinity indicates that at V = -73.6 mV half of the sodium currents were inactivated. Single channel current recordings demonstrated the occurrence of discrete events: the latency for first opening was shorter as the depolarizing pulse became more positive. The single-channel current amplitude was ohmic with a slope conductance, gamma = 17.13 pS +/- 0.66 pS. Sodium channel currents were reversibly blocked by tetrodotoxin (TTX).(ABSTRACT TRUNCATED AT 250 WORDS)
Brain Res Mol Brain Res 1990 Feb
PMID:Voltage-gated sodium channels expressed in the human cerebellar medulloblastoma cell line TE671. 216 39

During development, Myxococcus xanthus cells glide toward foci of aggregation and produce compact multicellular mounds. We studied development in strains with defects in contact-stimulated gliding. Contact stimulation involves a mechanism influenced by contacts between neighboring cells which stimulates the gliding motility of single cells (Hodgkin and Kaiser, Proc. Natl. Acad. Sci. USA 74:2938-2942, 1977; Hodgkin and Kaiser, Mol. Gen. Genet. 171:167-176, 1979). Most mutants containing a mutation in a single gene affecting contact stimulation (cgl gene) were able to form foci of aggregation during development. However, the aggregates were diffuse, suggesting that contact stimulation is important for morphogenetic movements during aggregation. A mutant containing a mutation in the cglF3 gene showed a striking delay in aggregation, suggesting that the cglF3 gene affects a mechanism stimulating cells moving to foci or affects a mechanism for coordinating early cell behavior. Mutants containing the cglF3 mutation in combination with a cglB, cglC, cglE, or cglF1 mutation had severe defects in aggregation and failed to recover from the early delay. The severity of the defects in mutants containing two cgl mutations suggests that cgl genes are critical for development. We propose that cgl genes stimulate cell movement or control specific contacts between cells during aggregation.
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PMID:Defects in contact-stimulated gliding during aggregation by Myxococcus xanthus. 217 15

We designed synthetic oligonucleotide primers and hybridization probe for use in polymerase chain reaction (PCR) amplification and hybridization detection of Epstein-Barr virus (EBV) nucleic acid sequences. Primer sequences were chosen from the coding region for the Epstein-Barr virus nuclear antigen-1 (EBNA-1). PCR amplification and hybridization with these oligonucleotides was carried out on standard laboratory cell lines including African Burkitt's lymphoma and infectious mononucleosis derived cell lines, as well as cell lines recently established from clinical EBV isolates from bone marrow transplant recipients. All EBV cell lines tested were positive. No false-positives were detected with uninfected cell lines, human placental DNA or with other viruses. The sensitivity of the detection procedure was such that four copies of the EBV genome could consistently be detected in a background of 1 microgram of placental DNA. EBV was detected in DNA extracts from the peripheral blood mononuclear cells of two patients with infectious mononucleosis and one patient with viral-associated hemophagocytic syndrome. Three of 18 EBV seropositive patients without known ongoing EBV-associated illness undergoing ambulatory surgery also had EBV detected in DNA extracts from their peripheral blood mononuclear cells. EBV was detected in DNA extracts from lymphoma tissue from two patients with post-transplant lymphomas and two AIDS patients with primary CNS lymphomas. EBV was not detected in 12 B-cell lymphoma specimens from patients without history of immunocompromise. DNA extracts from formalin-fixed paraffin-embedded Hodgkin's tissues previously shown to be EBV positive by Southern blot were also demonstrated to be EBV positive by PCR. Thus, with the oligonucleotides described, PCR is applicable to the detection of EBV in a spectrum of clinical isolates. The broad specificity of these oligonucleotides for all strains of EBV tested is probably a function of the highly conserved sequence of the EBNA-1 DNA binding domain.
Mol Cell Probes 1990 Oct
PMID:Oligonucleotides for polymerase chain reaction amplification and hybridization detection of Epstein-Barr virus DNA in clinical specimens. 217 46

The membrane molecule termed "7F7-antigen" has been found to be involved in several examples of cell-cell interactions. This 85 kDa glycoprotein with a protein core of about 55 kDa contains N-linked and O-linked carbohydrates. It has an isoelectric point of 8.0-8.5 and is expressed on 20% of peripheral blood mononuclear cells, 35% of peripheral blood B-cells, follicular dendritic cells and vascular endothelium. It is also expressed on activated T-cells and its expression on B-cells, fibroblasts and monocytes increases after treatment with PWM, interferon-gamma and after three days culture, respectively. The MAb 7F7 used to define this antigen inhibits the initiation of T-cell proliferation induced by anti-CD3, PHA, ConA and (weakly) allogenic stimulator cells, but does not affect the growth of IL-2 dependent T-cells and does not interfere with the killing of PHA-blasts by allogenic IL-2 dependent T-cells. 7F7 also inhibits the binding of C3-coated sheep erythrocytes to B-cells, the PMA-induced aggregation of U937 and the binding of activated T-cells to fibroblasts. The 7F7-antigen is expressed on some non-Hodgkin lymphomas of B-cell differentiation, particularly those with follicular structure, but not on Burkitt's lymphoma, ALL or carcinomas of various tissues. It is, however, found on fibrous tissue surrounding infiltrating carcinoma cells. The expression of a melanoma antigen, P3.58, which was shown to be identical to 7F7-antigen correlates with stage and spread of invasive melanoma. It was concluded that the 7F7-antigen, which is probably related to a previously described adherence molecule (ICAM-1), is of biological importance for the initiation of T-cell responses. With the possible exception of melanoma its expression on neoplastic cells in vivo is unlikely to be of importance for the spread of malignant disease.
Mol Immunol 1988 Nov
PMID:Importance of an 85 kDa membrane glycoprotein for a variety of cell-cell interactions. 246 58

A series of 217 trephine bone marrow biopsies from adult patients and specimens from 16 fetuses and 5 infants were examined for the presence of stromal myoid cells (MCs) using a monoclonal antibody recognizing alpha-smooth muscle actin. In the normal adult bone marrow, stromal cells did not contain alpha-smooth muscle actin, whereas during fetal life, many alpha-smooth muscle actin-containing MCs were connected with vascular sinusoids in the primitive bone marrow. This cell type reappeared in various characteristic distribution patterns in adult bone marrow during different neoplastic and non-neoplastic conditions including metastatic carcinoma, Hodgkin's disease, multiple myeloma, hairy cell leukemia, acute myeloid leukemia (FAB M4, 5, 7) and chronic myelo-proliferative diseases. In general, the appearance of MCs was associated with a slight to pronounced increase in the deposition of reticulin and collagen fibers. We propose that bone marrow MCs represent a distinct subpopulation of fiber-associated or adventitial reticular cells undergoing cytoskeletal remodeling in response to various stimuli.
Virchows Arch B Cell Pathol Incl Mol Pathol 1989
PMID:Alpha-smooth muscle actin is expressed in a subset of bone marrow stromal cells in normal and pathological conditions. 257 Apr 90

The aim of the study is to establish quantitative cytological criteria for reliable diagnoses in high grade malignant non-Hodgkin's lymphomas (NHL). For this purpose Pappenheim-stained cytologic imprints from 15 cases of high grade malignant NHL and ten cases of chronic tonsillitis have been analysed using a TV-microscope system, high resolution color scanning (13.3 pixel/microns), and image processing on a computer. The highly reliable computer-extracted cell features can be used to discriminate the different cell types of malignant NHL. Because of a considerable overlap, no feature on its own is sufficient to discriminate all the different cells. Only multivariate analysis of a suitable combination of features allows reliable discrimination. The results show that the different cells defined by subjective morphological criteria in the Kiel-classification of malignant NHL also form distinctive subpopulations with regard to their objective mathematical cell features and show distinctive differences when compared with their benign counterparts derived from reactive lymphatic tissue.
Virchows Arch B Cell Pathol Incl Mol Pathol 1989
PMID:Computer aided cytometry in high grade malignant non-Hodgkin's lymphomas and tonsils. 257 20

The abnormal cell population in lymphomatoid papulosis was studied by immunohistochemistry, light and electron microscopy in five cases. It resulted in a comprehensive description of all the main variants within the abnormal cell population. In one of the cases an irreversible intracytoplasmic process in the abnormal lymphocytes made it possible to demonstrate the derivation of lymphomatoid cells with cerebriform nuclei resembling the mycosis cells in mycosis fungoides from large histiocyte-like cells resembling the Reed-Sternberg cells in Hodgkin's disease. Variable numbers of the abnormal cells expressed Ki-1 reactivity in all four cases tested and T-cell associated antigens in two cases.
Virchows Arch B Cell Pathol Incl Mol Pathol 1987
PMID:Abnormal T-lymphocytes in lymphomatoid papulosis. A cytomorphological study with a reconstruction of a major part of the cell differentiation cycle. 288 64

Granulocyte/macrophage progenitor cells (CFU-GM) and erythroid progenitor cells (BFU-E) have been assayed in peripheral blood (PB) and/or bone marrow (BM) from 12 patients with acute lymphocytic leukemia (ALL), 16 patients with chronic lymphocytic leukemia (CLL) and 31 patients with various forms of non-Hodgkin lymphoma (NHL) without BM involvement. Progenitor cell growth in PB and BM from the NHL patients did not differ statistically from controls (p greater than 0.1). CFU-GM and BFU-E per ml PB were markedly increased in ALL and CLL patients (p less than 0.001) while CFU-GM and BFU-E per plated BM cells from these patients were severely depressed (p less than 0.001). Lymphoblasts from one ALL patient failed to inhibit CFU-GM and BFU-E-derived colony growth from control PB mononuclear cells. The high levels of circulating progenitor cells in ALL and CLL patients clearly distinguish them from other cytopenic hematological malignancies, in which decreased progenitor cell levels have been demonstrated previously (acute myeloid leukemia, hairy cell leukemia). The cause of this finding and its pathophysiological implication still remains to be established.
Virchows Arch B Cell Pathol Incl Mol Pathol 1987
PMID:In vitro culture studies of granulocyte/macrophage and erythroid progenitor cells in lymphoproliferative disorders. 288 76


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